It seems to be about city versus farm. The agricultural areas are low population density. Therefore they have less lock down. Therefore they have less unemployment.

The high unemployment areas are where people make their livings in contact with clients and customers. They were locked down.

If you wanted to conquer a country, you wouldn't burn its farms. You would be eating off them, later, after you win. No, instead you would burn its cities, because that's where the leadership class is. And where most of the people are, because farming is so efficient now that few people are needed on the farm.

This map isn't about Republican or Democrat areas, it seems to be about city versus farm. The agricultural areas are low population density. Therefore they have less lock down. Therefore they have less unemployment.

The high unemployment areas are where there is higher population density. People make their livings there being in contact with clients and customers. They were locked down.